/* * WPA Supplicant - RSN PMKSA cache * Copyright (c) 2004-2009, 2011-2015, Jouni Malinen <j@w1.fi> * * This software may be distributed under the terms of the BSD license. * See README for more details. */ #include "includes.h" #include "common.h" #include "eloop.h" #include "eapol_supp/eapol_supp_sm.h" #include "wpa.h" #include "wpa_i.h" #include "pmksa_cache.h" #if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA) static const int pmksa_cache_max_entries = 32; struct rsn_pmksa_cache { struct rsn_pmksa_cache_entry *pmksa; /* PMKSA cache */ int pmksa_count; /* number of entries in PMKSA cache */ struct wpa_sm *sm; /* TODO: get rid of this reference(?) */ void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx, enum pmksa_free_reason reason); void *ctx; }; static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa); static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry) { bin_clear_free(entry, sizeof(*entry)); } static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa, struct rsn_pmksa_cache_entry *entry, enum pmksa_free_reason reason) { wpa_sm_remove_pmkid(pmksa->sm, entry->network_ctx, entry->aa, entry->pmkid, entry->fils_cache_id_set ? entry->fils_cache_id : NULL); pmksa->pmksa_count--; pmksa->free_cb(entry, pmksa->ctx, reason); _pmksa_cache_free_entry(entry); } static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx) { struct rsn_pmksa_cache *pmksa = eloop_ctx; struct os_reltime now; os_get_reltime(&now); while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) { struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; pmksa->pmksa = entry->next; wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for " MACSTR, MAC2STR(entry->aa)); pmksa_cache_free_entry(pmksa, entry, PMKSA_EXPIRE); } pmksa_cache_set_expiration(pmksa); } static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx) { struct rsn_pmksa_cache *pmksa = eloop_ctx; pmksa->sm->cur_pmksa = NULL; eapol_sm_request_reauth(pmksa->sm->eapol); } static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa) { int sec; struct rsn_pmksa_cache_entry *entry; struct os_reltime now; eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL); eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL); if (pmksa->pmksa == NULL) return; os_get_reltime(&now); sec = pmksa->pmksa->expiration - now.sec; if (sec < 0) sec = 0; eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL); entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa : pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL, NULL); if (entry) { sec = pmksa->pmksa->reauth_time - now.sec; if (sec < 0) sec = 0; eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa, NULL); } } /** * pmksa_cache_add - Add a PMKSA cache entry * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() * @pmk: The new pairwise master key * @pmk_len: PMK length in bytes, usually PMK_LEN (32) * @pmkid: Calculated PMKID * @kck: Key confirmation key or %NULL if not yet derived * @kck_len: KCK length in bytes * @aa: Authenticator address * @spa: Supplicant address * @network_ctx: Network configuration context for this PMK * @akmp: WPA_KEY_MGMT_* used in key derivation * @cache_id: Pointer to FILS Cache Identifier or %NULL if not advertised * Returns: Pointer to the added PMKSA cache entry or %NULL on error * * This function create a PMKSA entry for a new PMK and adds it to the PMKSA * cache. If an old entry is already in the cache for the same Authenticator, * this entry will be replaced with the new entry. PMKID will be calculated * based on the PMK and the driver interface is notified of the new PMKID. */ struct rsn_pmksa_cache_entry * pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len, const u8 *pmkid, const u8 *kck, size_t kck_len, const u8 *aa, const u8 *spa, void *network_ctx, int akmp, const u8 *cache_id) { struct rsn_pmksa_cache_entry *entry; struct os_reltime now; if (pmk_len > PMK_LEN_MAX) return NULL; if (wpa_key_mgmt_suite_b(akmp) && !kck) return NULL; entry = os_zalloc(sizeof(*entry)); if (entry == NULL) return NULL; os_memcpy(entry->pmk, pmk, pmk_len); entry->pmk_len = pmk_len; if (pmkid) os_memcpy(entry->pmkid, pmkid, PMKID_LEN); else if (akmp == WPA_KEY_MGMT_IEEE8021X_SUITE_B_192) rsn_pmkid_suite_b_192(kck, kck_len, aa, spa, entry->pmkid); else if (wpa_key_mgmt_suite_b(akmp)) rsn_pmkid_suite_b(kck, kck_len, aa, spa, entry->pmkid); else rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid, akmp); os_get_reltime(&now); entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime; entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime * pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100; entry->akmp = akmp; if (cache_id) { entry->fils_cache_id_set = 1; os_memcpy(entry->fils_cache_id, cache_id, FILS_CACHE_ID_LEN); } os_memcpy(entry->aa, aa, ETH_ALEN); entry->network_ctx = network_ctx; return pmksa_cache_add_entry(pmksa, entry); } struct rsn_pmksa_cache_entry * pmksa_cache_add_entry(struct rsn_pmksa_cache *pmksa, struct rsn_pmksa_cache_entry *entry) { struct rsn_pmksa_cache_entry *pos, *prev; /* Replace an old entry for the same Authenticator (if found) with the * new entry */ pos = pmksa->pmksa; prev = NULL; while (pos) { if (os_memcmp(entry->aa, pos->aa, ETH_ALEN) == 0) { if (pos->pmk_len == entry->pmk_len && os_memcmp_const(pos->pmk, entry->pmk, entry->pmk_len) == 0 && os_memcmp_const(pos->pmkid, entry->pmkid, PMKID_LEN) == 0) { wpa_printf(MSG_DEBUG, "WPA: reusing previous " "PMKSA entry"); os_free(entry); return pos; } if (prev == NULL) pmksa->pmksa = pos->next; else prev->next = pos->next; /* * If OKC is used, there may be other PMKSA cache * entries based on the same PMK. These needs to be * flushed so that a new entry can be created based on * the new PMK. Only clear other entries if they have a * matching PMK and this PMK has been used successfully * with the current AP, i.e., if opportunistic flag has * been cleared in wpa_supplicant_key_neg_complete(). */ wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for " "the current AP and any PMKSA cache entry " "that was based on the old PMK"); if (!pos->opportunistic) pmksa_cache_flush(pmksa, entry->network_ctx, pos->pmk, pos->pmk_len); pmksa_cache_free_entry(pmksa, pos, PMKSA_REPLACE); break; } prev = pos; pos = pos->next; } if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) { /* Remove the oldest entry to make room for the new entry */ pos = pmksa->pmksa; if (pos == pmksa->sm->cur_pmksa) { /* * Never remove the current PMKSA cache entry, since * it's in use, and removing it triggers a needless * deauthentication. */ pos = pos->next; pmksa->pmksa->next = pos ? pos->next : NULL; } else pmksa->pmksa = pos->next; if (pos) { wpa_printf(MSG_DEBUG, "RSN: removed the oldest idle " "PMKSA cache entry (for " MACSTR ") to " "make room for new one", MAC2STR(pos->aa)); pmksa_cache_free_entry(pmksa, pos, PMKSA_FREE); } } /* Add the new entry; order by expiration time */ pos = pmksa->pmksa; prev = NULL; while (pos) { if (pos->expiration > entry->expiration) break; prev = pos; pos = pos->next; } if (prev == NULL) { entry->next = pmksa->pmksa; pmksa->pmksa = entry; pmksa_cache_set_expiration(pmksa); } else { entry->next = prev->next; prev->next = entry; } pmksa->pmksa_count++; wpa_printf(MSG_DEBUG, "RSN: Added PMKSA cache entry for " MACSTR " network_ctx=%p", MAC2STR(entry->aa), entry->network_ctx); wpa_sm_add_pmkid(pmksa->sm, entry->network_ctx, entry->aa, entry->pmkid, entry->fils_cache_id_set ? entry->fils_cache_id : NULL, entry->pmk, entry->pmk_len); return entry; } /** * pmksa_cache_flush - Flush PMKSA cache entries for a specific network * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() * @network_ctx: Network configuration context or %NULL to flush all entries * @pmk: PMK to match for or %NYLL to match all PMKs * @pmk_len: PMK length */ void pmksa_cache_flush(struct rsn_pmksa_cache *pmksa, void *network_ctx, const u8 *pmk, size_t pmk_len) { struct rsn_pmksa_cache_entry *entry, *prev = NULL, *tmp; int removed = 0; entry = pmksa->pmksa; while (entry) { if ((entry->network_ctx == network_ctx || network_ctx == NULL) && (pmk == NULL || (pmk_len == entry->pmk_len && os_memcmp(pmk, entry->pmk, pmk_len) == 0))) { wpa_printf(MSG_DEBUG, "RSN: Flush PMKSA cache entry " "for " MACSTR, MAC2STR(entry->aa)); if (prev) prev->next = entry->next; else pmksa->pmksa = entry->next; tmp = entry; entry = entry->next; pmksa_cache_free_entry(pmksa, tmp, PMKSA_FREE); removed++; } else { prev = entry; entry = entry->next; } } if (removed) pmksa_cache_set_expiration(pmksa); } /** * pmksa_cache_deinit - Free all entries in PMKSA cache * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() */ void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa) { struct rsn_pmksa_cache_entry *entry, *prev; if (pmksa == NULL) return; entry = pmksa->pmksa; pmksa->pmksa = NULL; while (entry) { prev = entry; entry = entry->next; os_free(prev); } pmksa_cache_set_expiration(pmksa); os_free(pmksa); } /** * pmksa_cache_get - Fetch a PMKSA cache entry * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() * @aa: Authenticator address or %NULL to match any * @pmkid: PMKID or %NULL to match any * @network_ctx: Network context or %NULL to match any * Returns: Pointer to PMKSA cache entry or %NULL if no match was found */ struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa, const u8 *aa, const u8 *pmkid, const void *network_ctx) { struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; while (entry) { if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) && (pmkid == NULL || os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0) && (network_ctx == NULL || network_ctx == entry->network_ctx)) return entry; entry = entry->next; } return NULL; } static struct rsn_pmksa_cache_entry * pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa, const struct rsn_pmksa_cache_entry *old_entry, const u8 *aa) { struct rsn_pmksa_cache_entry *new_entry; os_time_t old_expiration = old_entry->expiration; new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len, NULL, NULL, 0, aa, pmksa->sm->own_addr, old_entry->network_ctx, old_entry->akmp, old_entry->fils_cache_id_set ? old_entry->fils_cache_id : NULL); if (new_entry == NULL) return NULL; /* TODO: reorder entries based on expiration time? */ new_entry->expiration = old_expiration; new_entry->opportunistic = 1; return new_entry; } /** * pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() * @network_ctx: Network configuration context * @aa: Authenticator address for the new AP * Returns: Pointer to a new PMKSA cache entry or %NULL if not available * * Try to create a new PMKSA cache entry opportunistically by guessing that the * new AP is sharing the same PMK as another AP that has the same SSID and has * already an entry in PMKSA cache. */ struct rsn_pmksa_cache_entry * pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx, const u8 *aa) { struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; wpa_printf(MSG_DEBUG, "RSN: Consider " MACSTR " for OKC", MAC2STR(aa)); if (network_ctx == NULL) return NULL; while (entry) { if (entry->network_ctx == network_ctx) { entry = pmksa_cache_clone_entry(pmksa, entry, aa); if (entry) { wpa_printf(MSG_DEBUG, "RSN: added " "opportunistic PMKSA cache entry " "for " MACSTR, MAC2STR(aa)); } return entry; } entry = entry->next; } return NULL; } static struct rsn_pmksa_cache_entry * pmksa_cache_get_fils_cache_id(struct rsn_pmksa_cache *pmksa, const void *network_ctx, const u8 *cache_id) { struct rsn_pmksa_cache_entry *entry; for (entry = pmksa->pmksa; entry; entry = entry->next) { if (network_ctx == entry->network_ctx && entry->fils_cache_id_set && os_memcmp(cache_id, entry->fils_cache_id, FILS_CACHE_ID_LEN) == 0) return entry; } return NULL; } /** * pmksa_cache_get_current - Get the current used PMKSA entry * @sm: Pointer to WPA state machine data from wpa_sm_init() * Returns: Pointer to the current PMKSA cache entry or %NULL if not available */ struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm) { if (sm == NULL) return NULL; return sm->cur_pmksa; } /** * pmksa_cache_clear_current - Clear the current PMKSA entry selection * @sm: Pointer to WPA state machine data from wpa_sm_init() */ void pmksa_cache_clear_current(struct wpa_sm *sm) { if (sm == NULL) return; sm->cur_pmksa = NULL; } /** * pmksa_cache_set_current - Set the current PMKSA entry selection * @sm: Pointer to WPA state machine data from wpa_sm_init() * @pmkid: PMKID for selecting PMKSA or %NULL if not used * @bssid: BSSID for PMKSA or %NULL if not used * @network_ctx: Network configuration context * @try_opportunistic: Whether to allow opportunistic PMKSA caching * @fils_cache_id: Pointer to FILS Cache Identifier or %NULL if not used * Returns: 0 if PMKSA was found or -1 if no matching entry was found */ int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid, const u8 *bssid, void *network_ctx, int try_opportunistic, const u8 *fils_cache_id) { struct rsn_pmksa_cache *pmksa = sm->pmksa; wpa_printf(MSG_DEBUG, "RSN: PMKSA cache search - network_ctx=%p " "try_opportunistic=%d", network_ctx, try_opportunistic); if (pmkid) wpa_hexdump(MSG_DEBUG, "RSN: Search for PMKID", pmkid, PMKID_LEN); if (bssid) wpa_printf(MSG_DEBUG, "RSN: Search for BSSID " MACSTR, MAC2STR(bssid)); if (fils_cache_id) wpa_printf(MSG_DEBUG, "RSN: Search for FILS Cache Identifier %02x%02x", fils_cache_id[0], fils_cache_id[1]); sm->cur_pmksa = NULL; if (pmkid) sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid, network_ctx); if (sm->cur_pmksa == NULL && bssid) sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL, network_ctx); if (sm->cur_pmksa == NULL && try_opportunistic && bssid) sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa, network_ctx, bssid); if (sm->cur_pmksa == NULL && fils_cache_id) sm->cur_pmksa = pmksa_cache_get_fils_cache_id(pmksa, network_ctx, fils_cache_id); if (sm->cur_pmksa) { wpa_hexdump(MSG_DEBUG, "RSN: PMKSA cache entry found - PMKID", sm->cur_pmksa->pmkid, PMKID_LEN); return 0; } wpa_printf(MSG_DEBUG, "RSN: No PMKSA cache entry found"); return -1; } /** * pmksa_cache_list - Dump text list of entries in PMKSA cache * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() * @buf: Buffer for the list * @len: Length of the buffer * Returns: number of bytes written to buffer * * This function is used to generate a text format representation of the * current PMKSA cache contents for the ctrl_iface PMKSA command. */ int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len) { int i, ret; char *pos = buf; struct rsn_pmksa_cache_entry *entry; struct os_reltime now; int cache_id_used = 0; for (entry = pmksa->pmksa; entry; entry = entry->next) { if (entry->fils_cache_id_set) { cache_id_used = 1; break; } } os_get_reltime(&now); ret = os_snprintf(pos, buf + len - pos, "Index / AA / PMKID / expiration (in seconds) / " "opportunistic%s\n", cache_id_used ? " / FILS Cache Identifier" : ""); if (os_snprintf_error(buf + len - pos, ret)) return pos - buf; pos += ret; i = 0; entry = pmksa->pmksa; while (entry) { i++; ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ", i, MAC2STR(entry->aa)); if (os_snprintf_error(buf + len - pos, ret)) return pos - buf; pos += ret; pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid, PMKID_LEN); ret = os_snprintf(pos, buf + len - pos, " %d %d", (int) (entry->expiration - now.sec), entry->opportunistic); if (os_snprintf_error(buf + len - pos, ret)) return pos - buf; pos += ret; if (entry->fils_cache_id_set) { ret = os_snprintf(pos, buf + len - pos, " %02x%02x", entry->fils_cache_id[0], entry->fils_cache_id[1]); if (os_snprintf_error(buf + len - pos, ret)) return pos - buf; pos += ret; } ret = os_snprintf(pos, buf + len - pos, "\n"); if (os_snprintf_error(buf + len - pos, ret)) return pos - buf; pos += ret; entry = entry->next; } return pos - buf; } struct rsn_pmksa_cache_entry * pmksa_cache_head(struct rsn_pmksa_cache *pmksa) { return pmksa->pmksa; } /** * pmksa_cache_init - Initialize PMKSA cache * @free_cb: Callback function to be called when a PMKSA cache entry is freed * @ctx: Context pointer for free_cb function * @sm: Pointer to WPA state machine data from wpa_sm_init() * Returns: Pointer to PMKSA cache data or %NULL on failure */ struct rsn_pmksa_cache * pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx, enum pmksa_free_reason reason), void *ctx, struct wpa_sm *sm) { struct rsn_pmksa_cache *pmksa; pmksa = os_zalloc(sizeof(*pmksa)); if (pmksa) { pmksa->free_cb = free_cb; pmksa->ctx = ctx; pmksa->sm = sm; } return pmksa; } #endif /* IEEE8021X_EAPOL */